Property ‘value’ does not exist on type ‘Readonly<{}>‘

If you are encountering the error message “Property ‘value’ does not exist on type ‘Readonly<{}>‘” while working with JavaScript, you are not alone. This error usually occurs when you try to access or modify the ‘value’ property of an object that has been declared as ‘Readonly’. In this blog post, we will explore a few possible solutions to resolve this issue.

Solution 1: Type Assertion

One way to overcome this error is by using type assertion. Type assertion allows you to tell the TypeScript compiler the specific type of an object, even if it might not be known at compile-time. In this case, you can assert the object as a non-readonly type to access the ‘value’ property.

    const readOnlyObject: Readonly<{}> = { value: 'Hello' };
    const nonReadOnlyObject = readOnlyObject as { value: string };
    console.log(nonReadOnlyObject.value); // Output: Hello
  

Solution 2: Type Casting

Another solution is to use type casting. Type casting allows you to explicitly convert an object from one type to another. By casting the readonly object to the desired type, you can access the ‘value’ property without any errors.

    const readOnlyObject: Readonly<{}> = { value: 'Hello' };
    const nonReadOnlyObject = readOnlyObject as any;
    console.log(nonReadOnlyObject.value); // Output: Hello
  

Solution 3: Object Assignment

If you are working with an object that is declared as ‘Readonly’, you can create a new object and assign the properties of the readonly object to it. This new object will not have the ‘Readonly’ constraint, allowing you to access and modify the ‘value’ property.

    const readOnlyObject: Readonly<{}> = { value: 'Hello' };
    const nonReadOnlyObject = Object.assign({}, readOnlyObject);
    console.log(nonReadOnlyObject.value); // Output: Hello
  

These are three possible solutions to resolve the error “Property ‘value’ does not exist on type ‘Readonly<{}>‘”. Choose the solution that best fits your code and requirements. Happy coding!